Ultra short wave tube



Sept. 14, 1943. K. KOHL ULTRA SHORT WAVE TUBE Filed Nov. 27, 1940 INVENTOR ar| Kohl 5 %g H TTORNEY Karl Kohldterlin, Germany;: v ested in the Alien- Property "Gustodian For the transxi iis si on of j 'iiltra.

short waves, a number of arrangement''f eonh afs.

tions have been develd'ped of wl1ieh 'espeCi'ally the brake fizldlcnnctions' have prbtredftQ be Suitable for the sh'ortest waves. As is known; the ex citatin o'f the oscillations is understood to be effected in such a way that the electrons issued.

by an emission cathode are attracted with a great force by a highly positive electrodebut, owing to their proper vel0city attained thereby, they fiy past the electrode and on their further way are caused by an electric or magnetic brake field to turn back. The Whole process is performed by oscillations and may be influenced by a corresponding control and tuning of systems connected therewith, both according to the amplitude and with respect to the frequency. In spitze of all appliances employed, the action 0f these brake field connections is limited with respect to the effect obtained. 'Ihis effect Willb8 the smaller, the shorter the generated or transmitted wave is.

and' in'tentral longitudina1 section a simple emb0diment of the invention; 1

Fig. 2 illustrates in central transverse section and' in-ceritr2il longitudinal sectiori another am.- b'odifnent .of'the i'nVention, pr0viding a plurality 1 conoeritric eleCtron oscillation spaces;

Fig. 3 illustrates in central longitudinal section and in transverse section another embodiment of the invention.

Fig. 1 shows a constructiona1 example in the most simple form. I is a cathode capable of emitting electrons, 2 is a perforated grid-like anode to whicha high positive potential++is applied, 3 is a brake fie1d electrode. The above re ferred to cathode, anode, and electrode are encased. in an evacuated glass vessel 8. Conductors The present invention provides means for increasing the output of ultra short Wave energxr am). especially for extending towards ultra short waves the limit cf the possibility Cf genration or excitation.

According to the invention, the cathode or the brake field electrode is capable of emitting secondary electrons at a ratio to primary electmns greater than unity upon impact by such primary electrons. Instead of, er in conjunction with, said electrodes there may be provided additional separate auxiliary electrodes with an emission of secondaty electrons. The preferably sensitized brake electrode or auxiiiary electrode may be made on its part, due to the emission of secondary electrons, the source of a new oscillation so that there will result a cascade-like series connection of excited oscillation systems. The elec trodes may be arranged successively in one direction, asplane electrodes or'a1su in a circularly symmetrical construction as concentric cylinders. The individual e1ectrodes have to be perforated so as to permit the secondary electrons released on one side to pass through to the other side. Of course, the spaces between the electrodes and also the potentials or potential difierences applied must be adapted to the durations of a cycle er to the frequencies. The electrodes may also be conneoted with corresponding reso-nance systems, or may be constructed as such.

The invention is illustrated by way of con: structional examples in the accompanying drawinginwhich- Fig. 1 illustrates in central transverse section H, I2 and I3 are sea1ed in the Walls of the evacuated vessel 8 and are connected respectively ab their inner ends to the cathode I, anode 2 and electrode 3, it being understood that such son- -ductors are connected in the usual way when lt 15 desired to connect the same in a proper circuit. The brake field electrode possesses in the usual manner a, potential of zero voltage or a small positive or negative potential with respect to the cathode I. The brake electrode 3 is furnished with a sensitized 'covering 3, preferably consisting 05 silver with Sprayed onberyllium. In addition, the cathode l may be sensitized and, if necessary, also the anode 2, although here the action of the seconclary electrons is but small, since, owing to the high potentil the electrons are *at once picked up by the electr0de itslf.

Fig. 2 shows another arrangement inwhich severa1 electron oscillation spaces are disposed concentrically to one another. The first space is formed by the three electrodes l, 2, 3, and the second by the electrode system 3, 4, 5. Of course, Iurther systems could follow outside. The electrons oscillate in orbits indicated by the elliptical .ai'rows. In order that the electron oscillations shou1d not develop excessively in the space of the actual cathode I with respect to the other spaces it is advisable to let the electrode potentials of the anodes 2, 4, etc. increase from the centre to the outside, the potentials of the brake electrodes having to be adapted accordingly. In this way,

the secondary electrons are prevented from returning in too large numbers to the cathode I.

Fig. 3 shows a corresponding plane arrangement. The ultra, short wave energy may be de- :ived selectively from diflerent electrodes. Thus, for example, the anode 2 may be constructed with an external connecting hoop as a circle of spirals.

tion. Special mea;nS may be provide.d IQ! StibL- lizing the oscillations 0r the releasing of the electrons, in order 150 prevent the tube from being destroyed. Such means may consisi; of attenua.

tion members, or also of placing aslope the cath- Ode, which in this respect is particularlsl snsitaisr.

electrodes and brake electrodes adjacent to said cathode and adapted Ior emltting secondary e1ectrons, the accelerating and brake electrodes being .arranged alternately thus forming oscillating spaces, and the electrodes being perforated to allow part of the electrong to pass through.

2. An electron taube for ultra-short waves having a. centra-l elongated heatable cathode and a plurality of substantiall r cylindrica. l perforated accek2nt iz ig a nd 'brake ele'ctr0d8a Df 'different diameters arranged concentrically and alterna'cely,

tihe cathode and brake electrode being provided with a. covering adapted for emitting secondary (alectronsl Furthermore, the shifting of the generatidn:of i

the oscillations to the outer oscillatio.n sp' 8s,

not containing the ca.thode acts in a. stabflizingfi manner. Instead of or in conjunbti'on with' placing the cathode aslope, there may be eml-- 3. .An.electron t.ube having a heatable ca.thode 1'or emitting secondary electrons and a. plurality pi". a cgzeler ating and brake electrodes mounted altem'atfly adjacent said cathode in serial relationship with one of said electrodes spaced a predete'rmined distance from said cathode and the 9the r electrodes spaced progre ss ively farther from sa1d C8Mlod e prpviding a luralit y of substantially equai spapes therebetween whereby alternate ones 01 sa id electrodeg are eifective durir 1g operat1on to a.ct as accelerating and brake elec':trqdes. KARL KOHL. 

